This book constitutes the refereed proceedings of the 18th European Symposium on Computer Security, ESORICS 2013, held in Egham, UK, in September 2013. The 43 papers included in the book were carefully reviewed and selected from 242 papers. The aim of ESORICS is to further the progress of research in computer security by establishing a European forum for bringing together researchers in this area, by promoting the exchange of ideas with system developers and by encouraging links with researchers in related areas. The papers cover all topics related to security, privacy and trust in computer systems and networks.